JP Patent Publication 2010-78156A (hereinafter JP ‘156) and JP Patent Publication 2014-202238A (hereinafter JP ‘238) disclose known automatic clutch devices for automatically engaging and disengaging manual transmissions (MT) or automated manual transmissions (AMT).
The automatic clutch device disclosed in JP ‘156 is configured such that, when the clutch pedal is depressed, hydraulic pressure is generated in a master cylinder mechanically connected to the clutch pedal, and is supplied to a clutch release cylinder, the clutch release cylinder pivots a release fork, thereby pressing a release bearing, a pressure plate is pressed against a flywheel under the pressing force applied to the pressure plate from the release bearing, and the clutch device engages.
The automatic clutch device disclosed in JP ‘238 is configured, similar to the clutch device of JP ‘156, such that hydraulic pressure generated in the master cylinder by depressing the clutch pedal is supplied to a clutch release cylinder, the clutch release cylinder pivots a release fork, the release fork presses a release bearing, and the clutch device disengages.
Since the clutch device of either of JP ‘156 and JP ‘238 is configured to be engaged and disengaged by pivoting the release fork with the clutch release cylinder, such clutch devices tend to be large in size. Moreover, since such clutch devices require a hydraulic pump, and pipe connections between the hydraulic pump and the clutch release cylinder, a large installation space is needed for such clutch devices.
While the ambient temperature is low, hydraulic pressure used to activate the clutch release cylinder flows less smoothly in the pipes due to elevated viscosity of the hydraulic oil, thus deteriorating responsiveness of the clutch release cylinder.